Pancreatic neuroendocrine tumor and solid-pseudopapillary neoplasm: Key immunohistochemical profiles for differential diagnosis

Table 1 Immunohistochemical procedures

Antigen (Clone)	Manufacturer	Antigen retrieval	Dilution	Incubation
		solution/temperature/time		temperature/time
Synaptophysin (27G12)	Nichirei Biosciences, Tokyo, Japan	TB/105 °C/10 min	Prediluted	RT/30 min
Chromogranin A (polyclonal)	Dako Japan, Tokyo, Japan	CB/115 °C/10 min	1:500	RT/30 min
Pan-cytokeratin (AE1/AE3)	Dako Japan, Tokyo, Japan	TB/105 °C/10 min	1:100	RT/30 min
E-cadherin (36B5)	Thermo Scientific, Yokohama, Japan	TB/121 °C/10 min	1:20	RT/60 min
Progesterone receptor (IE2)	Roche Diagnostics, Tokyo, Japan	CB/115 °C/10 min	Prediluted	RT/30 min
Vimentin (V9)	Dako Japan, Tokyo, Japan	CB/100 °C/15 min	1:100	RT/30 min
α-1-antitrypsin (polyclonal)	Dako Japan, Tokyo, Japan	No retrieval	1:100	RT/30 min
CD10 (56C6)	Leica Microsystems, Tokyo, Japan	TB/105 °C/10 min	1:40	RT/30 min
β-catenin (β-Catenin-1)	Dako Japan, Tokyo, Japan	TB/105 °C/10 min	1:200	RT/30 min
Ki-67 (MIB-1)	Dako Japan, Tokyo, Japan	CB/100 °C/30 min	1:25	4 °C/overnight

TB: Tris-HCl buffer; CB: Citrate buffer; RT: Room temperature.

Table 2 Clinicopathological and morphological characteristics of neuroendocrine tumor (24 cases) and solid-pseudopapillary neoplasm (6 cases)

Case	Age	Sex	Clinical findings	Tumor location	Operation	Diameter (cm)	Mitotic	Ki-67	Grade	Solid or	PP
	(yr)						count	(%)	for NETs	Cystic	pattern
NET-1	31	F	MEN1	H	PD	4.5	0	0	1	Solid and Cystic	Absent
NET-2	57	F	MEN1	H, T	EC, DP	5.3	0	1	1	Solid	Absent
NET-3	51	F	MEN1	H, B, T, L	EC, DP, LR	6.0	0	0	1	Solid	Absent
NET-4	45	F	MEN1	B, T	DP	1.4	0	0	1	Solid and Cystic	Absent
NET-5	42	F	insulinoma	B	EC	1.0	0	0	1	Solid	Absent
NET-6	62	F	insulinoma	H	EC	1.2	0	0	1	Solid	Absent
NET-7	73	M	insulinoma	H	PD	1.5	0	0	1	Solid	Absent
NET-8	74	F	insulinoma	T	DP	1.0	0	0	1	Solid	Absent
NET-9	67	M	insulinoma	B	EC	0.9	1	0	1	Solid	Absent
NET-10	51	F	insulinoma	B	MP	1.1	7	2	2	Solid	Absent
NET-11	45	M		H	EC	2.3	0	0	1	Solid	Absent
NET-12	68	F		H	EC	0.5	0	0	1	Solid	Absent
NET-13	77	M		T	DP	0.9	1	0	1	Solid	Absent
NET-14	57	M		H	PD	1.5	1	0	1	Solid	Absent
NET-15	45	M		H	EC	0.9	2	0	1	Solid	Absent
NET-16	51	F		H	PD	2.5	0	1	1	Solid	Absent
NET-17	59	M		H	MP	1.8	1	1	1	Solid	Absent
NET-18	59	F		T	EC	2.3	1	1	1	Solid and Cystic	Absent
NET-19	40	F		T	DP	3.3	0	4	2	Solid and Cystic	Absent
NET-20	53	M		T	DP	5.5	2	3	2	Solid	Absent
NET-21	39	M		H, B, T	TP	16	3	0	2	Solid	Absent
NET-22	51	M		H	PD	7.0	7	4	2	Solid	Absent
NET-23	58	F		B	EC	1.8	1	0	1	Solid	Absent
NET-24	32	M		H	PD	2.3	0	0	1	Solid	Absent
SPN-1	26	F		H	EC	8.5	0	0	-	Solid and Cystic	Present
SPN-2	34	F		T	DP	7.0	1	1	-	Solid and Cystic	Present
SPN-3	20	F		T	DP	7.5	0	0	-	Solid and Cystic	Present
SPN-4	23	F		T	DP	13	0	0	-	Solid and Cystic	Present
SPN-5	43	F		B	MP	3.8	0	0	-	Solid and Cystic	Present
SPN-6	27	M		T	DP	4.3	0	0	-	Solid and Cystic	Present

NET: Neuroendocrine tumor; SPN: Solid-pseudopapillary neoplasm; MEN: Multiple endocrine neoplasia; H: Pancreatic head; B: Pancreatic body; T: Pancreatic tail; L: Liver; PD: Pancreatoduodenectomy; MP: Middle pancreatectomy; DP: Distal pancreatectomy: TP: Total pancreatectomy; EC: Enucleation; LR: Liver resection; PP: Pattern pseudopapillary pattern; -: Not assessed.

Table 3 Immunohistochemical profiles of neuroendocrine tumor and solid-pseudopapillary neoplasm

Case	Syn	CgA	CK	E-cad	PgR	Vim	αATP	CD10	βcat (N/C)
NET-1	++	++	++	++	-	-	+	++	-
NET-2	++	++	++	++	++	-	+	++	-
NET-3	++	++	++	++	++	-	++	++	-
NET-4	++	++	++	++	++	++	-	-	-
NET-5	++	++	+	++	++	-	-	-	-
NET-6	++	++	+	++	++	-	-	-	-
NET-7	++	++	++	++	++	-	++	-	-
NET-8	++	++	+	++	++	-	++	-	-
NET-9	++	++	-	++	-	-	-	-	-
NET-10	++	++	+	++	++	++	++	-	-
NET-11	++	++	-	++	++	-	+	-	-
NET-12	++	++	+	+	++	++	-	-	-
NET-13	++	++	++	++	++	++	-	-	-
NET-14	++	++	++	++	-	++	++	-	-
NET-15	++	++	++	++	++	-	-	-	-
NET-16	++	++	+	+	++	-	++	++	-
NET-17	++	++	++	++	++	-	-	++	-
NET-18	++	++	++	++	++	++	-	++	-
NET-19	++	++	++	++	++	++	-	-	-
NET-20	++	++	++	++	++	++	++	-	-
NET-21	++	++	++	++	++	-	++	-	-
NET-22	++	++	++	++	-	-	++	-	-
NET-23	++	+ (dot)	-	-	++	++	++	++	++
NET-24	++	+ (dot)	-	-	++	++	++	++	++
SPN-1	-	+ (dot)	-	-	++	++	++	++	++
SPN-2	-	+ (dot)	-	-	++	++	++	++	++
SPN-3	++	+ (dot)	+	-	++	++	++	++	++
SPN-4	++	+ (dot)	-	-	++	++	++	++	++
SPN-5	++	+ (dot)	-	-	++	++	++	++	++
SPN-6	++	+ (dot)	-	-	++	++	++	++	++

NET: Neuroendocrine tumor; SPN: Solid-pseudopapillary neoplasm; Syn: Synaptophysin; CgA: Chromogranin A; CK: Pan-cytokeratin; E-cad: E-cadherin; PgR: Progesterone receptor; Vim: Vimentin; αATP: α-1-antitrypsin; βcat (N/C): β-catenin (nuclear/cytoplasmic staining); ++: Strongly positive; +: Weakly positive; -: Negative; dot: Dot-like pattern.